The use of a foil including a layer of heat sensitive adhesive to close and seal containers such as milk bottles and pill bottles is well known. A punch and die arrangement punches a foil portion of the required size directly into the cap from a foil sheet fed through the punch and die. The foil portion is delivered to the container as part of the cap, and an electrical induction system heats the foil, melting the adhesive and sealing the foil to the rim of the container.